To identify determinants of mortality after hip fracture, we performed a multicenter, retrospective study of 390 Medicare beneficiaries. Independent predictors of 30-day mortality included a history of congestive heart failure (odds ratio [OR] 32; 95% confidence interval [CI] 5, 192), angina (OR 26; 95% CI 4, 184), or chronic pulmonary disease (OR 11; 95% CI 2, 62). Postoperative use of aspirin was associated with a reduced risk of mortality (OR 0.24; 95% CI 0.08, 0.70). Cardiovascular events were the presumed cause of 63% of in-hospital deaths. Aspirin may have significant potential to reduce mortality in this population and deserves further study.